Re: [ccp4bb] protein lost activity after size exclusion chromatography

2011-03-16 Thread Jacob Keller
I guess it depends on what your activity is. Can you divulge that? Could it be that Ni is necessary? Jacob On Wed, Mar 16, 2011 at 11:28 AM, Harvey Rodriguez h.rodriguez.x...@gmail.com wrote: Dear all, Recently, I came across an obstacle on the purification and acitivty measurement of my

Re: [ccp4bb] protein lost activity after size exclusion chromatography

2011-03-16 Thread Phoebe Rice
] protein lost activity after size exclusion chromatography To: CCP4BB@JISCMAIL.AC.UK I guess it depends on what your activity is. Can you divulge that? Could it be that Ni is necessary? Jacob On Wed, Mar 16, 2011 at 11:28 AM, Harvey Rodriguez h.rodriguez.x...@gmail.com wrote: Dear all

Re: [ccp4bb] protein lost activity after size exclusion chromatography

2011-03-16 Thread Justin Hall
Hi Harvey, Well, knowing nothing about your protein, allow me to ruminate anyway... It sounds like you are exploring the possibility of a metal ion or other cofactor being lost. This is a reasonable first thing to check, but your buffer exchange steps should allow small cofactors (smaller

Re: [ccp4bb] protein lost activity after size exclusion chromatography

2011-03-16 Thread alexandre wohlkonig
Hi Harvey, Could it be that the activity you're measuring comes from a contaminant? Did you test the other fractions from SEC or IEX? Cheers, Alex 2011/3/16 Harvey Rodriguez h.rodriguez.x...@gmail.com Dear all, Recently, I came across an obstacle on the purification and acitivty